The present invention relates to improvements in plastic film bags with pressure closable releasable rib and groove profile fasteners at the top.
In the development of thin plastic film bags, an objective to be served is to provide a bag which has pressure closable and reopenable continuous rib and groove profile fastener elements at the top. Such fastener elements must securely close the bag and resist accidental opening due to forces on the side walls of the bag which occur during stacking, handling and merchandising. In order to reduce the cost of the bag, the fastener profiles are made as lightweight as possible without jeopardizing the facility of the fasteners to hold the bag closed. The ability of the fastener to remain closed can be augmented by design of the fastener but also by design of the bag structure in relation to the fastener structure.
An object of the present invention is to provide an improved bag structure and method of making same wherein the bag has a reclosable fastener at the top and can withstand pulls and shocks from handling and from the contents without accidental opening of the bag fastener.
A further object of the invention is to provide an improved method of making a bag structure wherein the structure can be rapidly and easily fabricated without unnecessary and noneconomical time-consuming steps.
A further object of the invention is to provide an improved bag structure which has a greater resistance to opening.
Another object of the invention is to provide an improved method of making a flexible plastic bag having a reclosable fastener at the top wherein a unique handling and structuring of the bag material is employed so as to obtain a bag which opens more easily from the outside than from the inside.